3 things to watch on MLS Decision Day: Playoffs, seeding, trophies on the line

This Sunday, all 20 teams in Major League Soccer will pair up and square off in one final match of the regular season.

It's called MLS Decision Day, and with its completion, a few season-long questions will finally be answered: Which 12 teams are heading to the MLS postseason? Who will win the MLS Supporters' Shield? What teams will earn a bye or a home fixture in the first round of playoff action?

With a full slate of matches to keep an eye on, here are three things to watch for on October 25:

Locked horns in the battle for the Shield

Neutral fans should want to keep an eye on the battle for the number one spot in the league, being contested between FC Dallas and the New York Red Bulls. It's a battle of the Western versus Eastern Conferences, as only one team can stand victorious at the end of the season, triumphant with the MLS Supporters' Shield in hand.

The Shield is a trophy awarded to the team with the most points at the end of the regular season; the Red Bulls and the Hoops are currently deadlocked at 57 points each, with one game remaining in the season.

Both teams are also deadlocked in the first tie-breaker, which is number of wins, with 17 victories each. New York leads Dallas by six (18-12) in the second tie-breaker of goal differential.

The Red Bulls will travel to the Windy City to visit the last-place Chicago Fire, while FC Dallas hosts the San Jose Earthquakes. That latter game will be of great importance for fans of both the Hoops and Quakes, because of the Western Conference's still-murky playoff picture.

Playoff places are still up for grabs

Here's what you need to know about the playoff hunt ahead of the final day: the Red Bulls, D.C. United, Columbus Crew, Toronto FC, and Montreal Impact have all clinched berths in the Eastern Conference playoffs.

There is one spot remaining up for grabs in the East. The New England Revolution have a firm grasp on it, and need a win or a draw to secure it permanently. But Orlando City is still alive, albeit barely; they need to overturn an eight-goal differential, plus hope the Revs lose in order to qualify miraculously.

So, for example, if Orlando beats the Philadelphia Union 5-0, and New York City FC defeat the Revs 4-0, then Orlando will qualify and New England will be eliminated. It's almost impossible, but in soccer, anything can happen.

The Western Conference picture is even more confusing. FC Dallas, the LA Galaxy, and the Vancouver Whitecaps have clinched their playoff spots; the Portland Timbers, Seattle Sounders, Sporting Kansas City, and the Earthquakes all remain in contention, with just three points separating the four teams and only three spots remaining in the standings.

When all is said and done, one team from each conference will be eliminated. For those who do make it, and for those who don't, though, there's still one more layer to consider.

Seeding, standings and a Canadian derby

There's still the matter of conference seeding to consider on the final day of the season. The top two teams in each conference earn an automatic bye, and advance straight into the home-and-away semi-final stage.

Meanwhile, the other four sides in each conference face off in a one-match wild-card round, with the fifth and sixth-placed teams travelling to the third and fourth-place teams' respective home stadiums.

Some key matches for seeding include Columbus versus D.C. United, and the Whitecaps facing the Houston Dynamo. Wins could propel any of the Whitecaps, Crew, or United into the bye-week spots, while losses could see them drop down to the wild card.

While we don't yet know which teams will be fighting for seeds just yet, especially in the West, there is one match of significant importance in this category.

It is, perhaps, the fiercest rivalry in any professional sport to happen north of the border: Toronto against Montreal. And on Sunday, Toronto FC travels up Highway 401 to take on the Impact, in a game that will decide which of these two teams will host a home playoff game in the first round of the postseason.

Toronto can finish as high as second place if other results go its way, as low as sixth if Montreal and New England both win, or anywhere else in between. It makes this 401 Derby game so important for both sides, and makes this matchup the hottest of the lot on Decision Day.

One last thing: the Golden Boot

Keep an eye on the TFC match, as well as the Galaxy-Sporting KC game, as the MLS Golden Boot race comes to a close. Kei Kamara has been eliminated from contention after being suspended with yellow card accumulation, despite having 22 goals.

That's the same tally as Sebastian Giovinco has, but with more assists, Giovinco already has one hand on the title and doesn't even need to score. Barring a Robbie Keane four-goal upset, the Golden Boot is all but assured for the Atomic Ant.